The rally in Western Australia was organised by the Construction, Forestry, Mining and Energy Union WA, the Australian Manufacturing Workers Union, the Communications, Electrical and Plumbing Union WA and the Maritime Union of Australia.

"It's good see all the blue collar unions in Western Australia working as one and that's how we're going to beat them at the end of the day," CFMEU WA state secretary Mick Buchan told the crowd.

"We make no apology for the resource magnates that they should be compelled to employ local workers and Australian citizens and residents first, before seeking overseas workers.

"We have a moral obligation to address the high levels of youth unemployment and indigenous unemployment in all parts of Australia.

"Resource and construction workers must provide more apprentices in training young Australians and up-skilling those that have been made redundant throughout the country.

"Before [enterprise migration agreements] are granted, we want to see proper market testing, we want to see training programs for real jobs and finally we want to see any EMA which may be approved is left to the scrutiny and made public for everyone to examine once it's available."

Police and security were present at Parliament House although the crowd remained orderly and controlled.

The sea of protestors, some dressed in high visibility clothing, held union flags and chanted songs which were mainly attacks on Chevron and Gina Rinehart.

In response to the rally, Chamber of Minerals and Energy chief executive Reg Howard-Smith told sister publication MiningNews.net the resources sector was committed to training the new wave of employees and that between September 2009 and September 2011 the sector had increased the number of apprentices and trainees by 72.5%.

Howard-Smith said the sector had the highest retention rate, with only 22% of apprentices in the resources sector withdrawing from their course in 2010 compared with 45% of apprentices across all industries.

"Industry's first priority is employing local people," Howard-Smith said.

"Skilled migration is an expensive last resort, particularly when you consider overseas recruitment searches, relocation expenses and paying Australian wages and conditions.

"It's good economics and good business to utilise Australian employees first."

Howard-Smith said WA was facing a skills shortage, not a general labour shortage, with the occupations currently in high demand including engineers of all disciplines, geologists, fitters, surveyors, electricians and metallurgists.

"As the resources sector gets busier there are significant flow-on effects to other sectors across WA and it is important for all employers to be able to source labour in a timely manner," he said.

"Where local skilled workers are not available, targeted skilled migration has a vital role to play in assisting industry fill its labour needs."